This invention relates to a connector for anchoring a first building structural member to a second building structural member. The connector works in conjunction with a separate anchor member that is received by or is attached to the second building structural member and with fasteners for attaching the connector to the first building structural member.
Earthquakes, hurricanes, tornadoes, and floods impose forces on a building that can cause structural failure. To counteract these forces, it has become common practice to strengthen or add ties between the structural members of a building in areas where such cataclysmic forces may be imposed. For example: framed walls can be attached to the foundation rather than merely rest on it; connections between the framed walls of each floor can be strengthened; and joists can be connected to both their headers and the walls that support the headers. One of the most common connectors designed for this application is called a holdown by the inventor. Holdowns are commonly used to anchor framed walls to the foundation.
Early holdowns were constructed from two or more separate pieces of metal welded together. These holdowns had to be painted to prevent rusting. They were heavy and costly to produce.
State of the art holdowns are made from galvanized sheet metal formed on progressive die machines that require no welding or painting. See U.S. Pat. No. 4,665,672, granted May 19, 1987, to Commins, Gilb and Littleton; U.S. Pat. No. 5,092,097 granted Mar. 3, 1992, to Young; and U.S. Pat. No. 5,249,404, granted Oct. 5, 1993, to Leek and Commins. These advancements have reduced the cost of making holdowns while increasing their ability to withstand tension forces. However, recent severe earthquakes in San Francisco, Los Angeles, and Kobe, Japan, demonstrate that holdowns capable of being mass produced and installed inexpensively should be made even stronger for many connections.
Generally, holdown connectors that work in conjunction with a separate anchor member and attach to only one face of the first building structural member--generally a vertically disposed stud--work in a common fashion. The anchor member attaches at the seat of the connector. This seat is connected to a back member. The back member attaches to the first building structural member. Most holdown connectors have one or more side members to increase the strength of the connector or to connect the seat member to the back member.
The holdown connector of the present invention works in a similar fashion to most of the prior art holdowns, such that it is amenable to standard installation practices. The holdown connector of the present invention improves on the prior art by accommodating variations in the position of the anchor member parallel to the face of the first building structural member to which the holdown connector attaches. The holdown connector of the present invention also withstands high tension loads while being economical to produce.